How exactly does Angelina design games?
In any case, it appears that much of his past work on Github involves procedural generation. Which is AI... ish. Unless there's more to it, which we can't see because half the site is down.
This paper appears to offer an analysis of combining procedural generation with game AI.
From the abstract:

Populated and immersive game contexts require large numbers of minor,
background characters to fill out the virtual environment. To limit
game AI development effort, however, such characters are typically
represented by very simplistic AI with either little difference
between characters or only highly formulaic variations. Here we
describe a complete workflow and framework for easily designing,
generating and incorporating multiple, interesting game AIs. Our
approach uses high-level, visual Statechart models to represent
behaviour in a modular form; this allows for not only simplistic,
parameterbased variation in AI design, but also permits more complex
structure-based approaches. We demonstrate our technique by applying
it to the task of generating a large number of individual AIs for
computer-controlled squirrels within the Mammoth 1 framework for
game research. Rapid development and easy deployment of AIs allow us
to create a wide variety of interesting AIs, greatly improving the
sense of immersion in a virtual environment.

Here's an article from 2015 on AI and procedural generation, which discusses Angelina at length. This article links to a more in-depth article from 2013.
Here's an excerpt:

Cook gave ANGELINA the ability to learn about people so that it could
make games based on current events. Then Cook gave ANGELINA memory -
that is, the ability to keep track of the people it had learned about.
The memory's not a big deal, even though it led to a number of
philosophical disagreements around Cook's desk. ANGELINA's memory is
actually just a text file where it stores the names of all the people
it's heard of, alongside a number: a measure of its opinion of them
based on the things it's learned from internet chatter. It liked
Al-Assad more than May. It liked everyone more than May.